Manufacture of filling or stuffing material.



UNITED STATES ROBERT JOHNCALDWELL, on NEW soUTHGATE, A1vn FRITZ ENGLAND.

PATENT OFFICE.

P LE MER, or LONDON,

MANUFACTURE OF-FILLING on sTUFrrNG MATERIAL.

No Drawing.

i useful Improvements in the Manufacture of Filling or Stufiing Materiahof which the following is a specification.

This invention relates toimprovements in the manufacture of an elastic cellular or foamy or spongy material for use as anelastic filling or stufling for hollow vehicletires, cushions, seats, mattresses, balls, buffers,

, elastic saddles, ships fenders, upholstery and then acted upon by a stirred a neutral the like, said filling or stuffing being of the kind wherein gelatin, glycerin and. preferably also a finely powdered material, such as zinc oxid, are mixed together at an ele- Vated temperature and stirred or beaten into a foam or sponge with a gas and are coagulating or tanning material in the presence of an oxidizing medium, the action of the said coagulating or tanning material being controlled by a substance that prevents premature coagulas tion or tanning ofthe gelatin, such as is described in thespecification of British Letters Patent No. 2796 of 1908.

Now according to the present invention, instead of mixing the tanning agent with an absorbent owder before it is brought into contact with the gelatin-mixture in the boiler or closed vessel in which the heating or stirring into a foam takes place, the tanning agent, which preferably consists of a strong solution of pyrogallol, is rendered viscous with gelatin or with gelatin and glycerin or other substances before it is introduced into the said boiler or closed vessel so as to enable it to mix more readily With the contents of said vessel and the action of the said tanning agent iscontrolled or restrained by adding to the air or like gas with which the mixture is beaten ,or gas, such asnitrogen, or by adding a reducing or acidic substance, such as sodium sulfite, citric acid, sulfurous acid, a bisulfite, or carbon dioxid to said mixture.

, Specification of Letters Pat entr Application filed July 6, 1909. V Serial-N0. 506,116.

in the foamy mass.

Patent ,Patentea Feb. 8, 1910.

The improved process of manufacture may be advantageously carried into practice as follows, viz: 1 owdered gelatin or glue is mixed with finely powdered zinc oxid or other fine insoluble powder, andthe mixture soaked in glycerin. The proportions will vary with the quality of the ingredients but should be such that a very viscous fluid. of

high surface tension results: at about 70 C.

The mixture isplaced in a boiler, preferably cylindrical, heated (usually in a waterbath) to a convenient temperature, usual ly about andis churned up by a stirrer toa foam with air at ordinary pressure. The

time required forthis operation depends on the speed and shape of the stirrer and the temperature but usually about 1 hour suffices. The stirrer is electrically driven so that, by means of a watt-meter or other suitable electric measuring instrument, itis possible to ascertain the relative viscosity of the mass at any moment, from the amount of power consumed by the stirrer. When as much air as possible has been beaten into the material, air or other gas or gases is pumped into the boiler until the pressure attains to from 5 to 50 atmospheres according to requirements. By this means, the foamy mass is pressed together again almost to its original bulk. The stirring is continued under pressure until the material is again of a foamy consistency, being impregnated with bubbles of air under high pressure. Since the oxygen of the air isa participant in. the subsequent chemical processes, it is possible to reduce both the speed and extentof the oxidation by reducing the amount of oxygen For this purpose, it is convenient to employ, as the gas with which the material is beaten into a foam, instead of. air only under pressure, a compressed mix ture of air and a neutral gas such as carbon dioxid or nitrogen. On the other hand, if

a higher degree of oxidation be required, 5 oxygen may be mixed With the compressed air, as in the specification of said British No. 2796 of 1908. The rate of stirring must be so regulated that, while a uniformly fine foam without large bubbles is produced, the material is not too long under high pressure, as in this caseit becomes somewhat oxidized or perhaps dissolves oxygen 1 dioxid is that of a diluent gas and also that so that the subsequent tanning operations proceed at an ungovernable rate.

When a foam of the right consistency has been prepared a tanning or hardening agent is introduced. It is well known that many substances, such as hydroquinone, tannin, pyrogallol, gallic acid, have the power, when in presence of oxygen, of rendering gelatin glutin) infusible and insoluble in water. In the present case, pyrogallol is the most convenient agent on account of its great solubility. A strong solution of pyrogallol, rendered viscous with gelatin or gelatin and glycerin or other substances is. introduced into the boiler. It is better to render the solution viscous in the way described since a mobile liquid does not readily mix with the viscous foam and produces a local destruction of the cell walls. A suitable proportion of gelatin for this purpose is per cent. by

weight of the liquid solvent of the tanning material. The tanning solution is placed in a cylinder, connected to the boiler by a suit-- able cock, and inclosed at the back with a piston, the other side of which is put into communication through a suitable cock or valve, with a reservoir of gas under high pressure, 0. g. 100. to200 atmospheres. By this means, the tanning liquid is driven into the boiler with apressure of 100 to 200 atmospheres when the cocks are opened.

The tanning solution is injected at the v end of the boiler and distributes itself throughout the length of the boiler. The stirrer is then'set 1n motion at a suitable velocity to mix the contentsof the boiler thoroughly before they become too viscous to be stirred. As the tanning process proceeds,-

more and more electric energy is required to operate the stirring mechanism. After a few minutes, when the watt-meter or other instrument registers a certain predetermined value, the stirrer is stopped, samples of material are taken out from a special cock provided for the purpose, and the material is quickly filled into the tires, cushions, etc., prepared for it. During the slow cooling of the material in the tires, etc., the tanning process completes itself so that the finished product will by no means flow out of the hole it entered by. Since, in spite of the admixture of neutral or diluent gases with the air in the foam, the tanning process in the case of many qualities of gelatin still proceeds inconveniently fast, it is often de sirable to add a restrainer to the tanning solution before introducing it into the boiler. A reducing agent such as sodium sulfite or citric acid is suitable for this purpose. Or since the action of pyrogallic acid proceeds best in an alkaline or neutral medium the tanning may be retarded by the admixture of acidic substances. The action of carbon in preparing a heated mixture of glycerin and gelatin, stirring the said mixture into a foam or sponge with a gas, preparing a solution of a tanning material, adding gelatin to said tanning-material solution to render the same viscous, and mixing said viscous solution with said foam or sponge in the presence of an oxidizing agent.

2. A process of making elastic cellular or spongy material for filing vehicle tires, cushions and the like, said process consisting in mixing together gelatin, glycerin and a finely powdered material at an elevated temperature, stirring said mixture into a foam or sponge witha gas, pre aring'a solution of a tanning material, adding gelatin to said tanning-material solution to render the same viscous, and mixing said viscous solution with said foam or sponge in the presence of an oxidizing agent.

3. A process of makin elastic cellular or spongy material for filing vehicle tires, cushions and the like, said process consisting in preparing a heated mixture of glycerin and gelatin, stirring the said mixture into a foam or sponge with a gas, preparing a solution of a tanning material, and m xing said. solution with said foam or sponge in the presence of an oxidizing agent and a chemical restrainer.

4. A process of making elastic cellular or spongy material for filling vehicle tires, cushions and the like, said process consisting in mixing together gelatin, glycerin and a finely powdered material at an elevated temperature, stirrin said mixture into a foam or sponge with atmospheric air and nitrogen, preparing a solution of a tanning material, adding gelatin to said tanningmaterial solution, and mixin said tanningmaterial solution with said fbam or sponge in the presence of an oxidizing agent.

5. A process of making elastic cellular or spongy material for filing vehicle tires, cushions and the like, said process consisting i1. stirring a viscous material containing gelatin and glycerin into a foam with a gas, adding a tanning material in solution, and stirring the mixture in the presence of an oxidizing agent, and a chemical restrainer the power required for stirring being continuously measured.

6. A process of making elastic cellular agent and a chemical restrainer, the power 10 required for stirring being contmuously measured.

ROBERT JOHN CALDWELL. FRITZ PFLEUMER.

Witnesses:

GEO. HARRISON,

CONRAD K. FALKENSTEIN. 

